13 And it shall come to pass, if ye shall hearken diligently unto my commandments which I command you this day, to love Jehovah your God, and to serve him with all your heart and with all your soul, 14 that I will give the rain of your land in its season, the former rain and the latter rain, that thou mayest gather in thy grain, and thy new wine, and thine oil. 15 And I will give grass in thy fields for thy cattle, and thou shalt eat and be full. 16 Take heed to yourselves, lest your heart be deceived, and ye turn aside, and serve other gods, and worship them; 17 and the anger of Jehovah be kindled against you, and he shut up the heavens, so that there shall be no rain, and the land shall not yield its fruit; and ye perish quickly from off the good land which Jehovah giveth you.

18 Therefore shall ye lay up these my words in your heart and in your soul; and ye shall bind them for a sign upon your hand, and they shall be for frontlets between your eyes. 19 And ye shall teach them your children, talking of them, when thou sittest in thy house, and when thou walkest by the way, and when thou liest down, and when thou risest up. 20 And thou shalt write them upon the door-posts of thy house, and upon thy gates; 21 that your days may be multiplied, and the days of your children, in the land which Jehovah sware unto your fathers to give them, as the days of the heavens above the earth.

Matthew Henry's Commentary on Deuteronomy 11:13-21

Commentary on Deuteronomy 11:8-17

(Read Deuteronomy 11:8-17)

Moses sets before them, for the future, life and death, the blessing and the curse, according as they did or did not keep God's commandment. Sin tends to shorten the days of all men, and to shorten the days of a people's prosperity. God will bless them with an abundance of all good things, if they would love him and serve him. Godliness has the promise of the life that now is; but the favour of God shall put gladness into the heart, more than the increase of corn, and wine, and oil. Revolt from God to idols would certainly be their ruin. Take heed that your hearts be not deceived. All who forsake God to set their affection upon any creature, will find themselves wretchedly deceived, to their own destruction; and this will make it worse, that it was for want of taking heed.

Commentary on Deuteronomy 11:18-25

(Read Deuteronomy 11:18-25)

Let all be directed by the three rules here given. 1. Let our hearts be filled with the word of God. There will not be good practices in the life, unless there be good thoughts, good affections, and good principles in the heart. 2. Let our eyes be fixed upon the word of God, having constant regard to it as the guide of our way, as the rule of our work, Psalm 119:30. 3. Let our tongues be employed about the word of God. Nor will any thing do more to cause prosperity, and keeping up religion in a nation, than the good education of children.